This special feature was developed following the public symposium held at the 30th Annual Meeting of the Japan Society for Disaster Information Studies on Saturday, March 15, 2024. On August 8, 2024, the "Nankai Trough Earthquake Extra Information" was issued for the first time since the system commenced operation. The public response to this information varied widely, and several challenges were observed in its practical use.

In light of these issues, a symposium was convened to consider how this information could be utilized from a disaster preparedness perspective. Experts involved in designing the system were invited to give keynote presentations, followed by a panel discussion on ways to make use of this information, incorporating diverse perspectives from the media, local governments, and other stakeholders.

This article serves as a summary of the key discussions and insights from the symposium. It highlights the importance of sharing and examining various viewpoints on how earthquake-related information can be connected to practical efforts for minimizing damage.

This paper investigates the Nankai Trough Earthquake Extra Information system, launched by the Japan Meteorological Agency (JMA) in 2019, and its initial deployment on August 8, 2024, following the Hyuganada earthquake. I first outline the system's framework, encompassing four information levels and corresponding governmental actions. I then detail the sequence of information releases in August 2024 and January 2025. Emphasizing that the system provides a probabilistic assessment of earthquake occurrence, distinct from prediction, especially given the complex potential of the Nankai Trough earthquakes including linked events, I analyze the operational dynamics and societal responses to the "Megathrust Earthquake Attention" issued on August 8, 2024. My discussion further examines sector-specific preparedness considerations (local government, transportation, education, healthcare) and identifies challenges in ensuring effective communication and promoting autonomous local and individual disaster readiness. This study aims to enhance understanding of the Extra Information system and contribute to improved disaster mitigation strategies.

Countermeasures against earthquakes and tsunamis along the Nankai Trough trace their origins to the establishment of the "Expert Committee on the Tokai Earthquake" by the Central Disaster Management Council following the 2001 governmental reorganization. In 2004, a dual-track strategy was implemented to prepare for both the Tokai and Tonankai–Nankai earthquakes. These measures were based on the expectation of sudden-onset seismic events, with the Tokai Earthquake uniquely addressed through a predictive framework under the Act on Special Measures Concerning Countermeasures for Large-Scale Earthquakes (hereafter, the “Large-Scale Earthquake Countermeasures Act”).

Following the 2011 Great East Japan Earthquake, policy discussions concerning countermeasures for Megathrust earthquakes and tsunamis—including those targeting the Tokai Earthquake—determined that reliable prediction is not yet scientifically feasible. As a result, the prediction-based approach outlined in the Special Large-Scale Earthquake Act underwent reassessment. Despite significant uncertainty associated with anomalous seismic observations, it became essential to develop emergency protocols focused on minimizing secondary damage and maintaining societal stability.

This evolution in policy culminated in the establishment of the Nankai Trough Earthquake Extra Information system, signifying a pivotal transition from prediction-based strategies to a risk-based disaster response paradigm.

In May 2019, the Japan Meteorological Agency began issuing emergency information on the Nankai Trough earthquake when the possibility of a major earthquake occurring in the Nankai Trough increased. However, this was not well known because the situation in which the information was issued was rare and the response was voluntary. When the emergency information on the Nankai Trough earthquake (Caution for a Major Earthquake) was issued in August 2024, various agencies were confused and perplexed in their response. I believe there are still many issues regarding the operation of this information. To solve these issues, I propose that, based on the efforts made by Shizuoka Prefecture so far, the framework of the Act on Special Measures for Large-Scale Earthquake Countermeasures be used to thoroughly implement earthquake disaster prevention measures.

The first point is to secure financial resources and promote disaster prevention measures in advance for a major earthquake in the Nankai Trough. The second point is to replace the earthquake prediction information, which is currently out of operation, with the new framework of emergency information on the Nankai Trough earthquake, and to position the reconfirmation and strengthening of earthquake disaster prevention measures for a certain period of time when the possibility of an earthquake occurring increases. I believe that such a response will minimize disruption to social activities.

Nankai Trough Earthquake Extra Information is an information system consisting of two response levels based on three types of observation criteria. This information was initiated as a result of the conclusion that earthquake prediction is not possible, and the core observation items for issuing the information are conservative and do not involve observational difficulties, focusing on the occurrence of earthquakes with a magnitude of 7 or higher. Under these conditions, the probability of a subsequent major earthquake occurring is extremely low. Therefore, the principle for disaster prevention measures is to avoid significant social impact and to reaffirm everyday earthquake preparedness. Furthermore, considering the high probability that an earthquake will not occur even if the information is released, rules have been established to lift disaster prevention measures after one or two weeks. These rules are based on the limits of social tolerance and cannot be determined based on seismological observations. These two rules—not implementing measures with significant social impact and automatically ending the response period over time—are believed to have been introduced as lessons learned from the previous earthquake prediction system for the Tokai earthquake. It is important to understand the history of how the Tokai earthquake prediction system had become scientifically unrealistic.

In this paper, the efforts to develop social scenarios during the extra information announcement of the Nankai Trough earthquake, as part of the Ministry of Education, Culture, Sports, Science and Technology's Science and Technology Research Commissioned Project, “Nankai Trough Earthquake Research Project Contributing to Disaster Prevention Measures.” A database of newspaper articles related to the extra information (catastrophic earthquake warning) announced during the Hyuga-nada earthquake on August 8, 2024, was developed. The results of text mining suggest that at the time of the August 8 extra information announcement (catastrophic earthquake warning), society did not experience chaos, panic, or extreme activity restriction but rather remained relatively stable. In addition, it was indicated that the importance of efforts to enhance understanding of the Nankai Trough earthquake and the necessity for citizens to actively prepare for it on their own initiative.

A questionnaire survey was conducted to assess the status of social welfare facilities at the time of the extra information announcement. As a result, it was revealed that the social welfare facilities surveyed strongly felt the risk of damage from the Nankai Trough earthquake. Using the outcomes from the extra information workshops and study works, it was developed the scenario situation data for the Nankai Trough earthquake extra information announcement. Also, it was pointed out that it is essential to implement the developed scenario data as situational input for the Nankai Trough earthquake extra information tabletop exercise and to revise Nankai Trough earthquake countermeasures and Business Continuity Plan (BCP).

If the general public understood the first of the three principles of evacuation, "Do not be overconfident about disaster assumptions," to mean that we should avoid downward expectations and only aim for upward expectations, then this understanding would be insufficient. Under certain conditions, our attempt to implement the second principle, "do your best," requires downward expectations. However, the limited understanding of the first principle, as mentioned above, could discourage us from doing the second principle. In order to avoid such a situation, the first argument of this study is to confirm that there are situations in which understanding that the first principle is a concept that allows for downward expectations plays a major role.

The second argument of this paper is the possibility that the sense of awkwardness that arises when trying to put the third principle, “be the first to evacuate,” may simply be a misconception. If the above sense of awkwardness was a misconception, it should be entirely possible to create a society where people do not feel awkwardness even when they evacuate first. The discussion also suggested that it would be possible to prepare such a society in advance through methods other than the third principle. Such a society would likely be one where, compared to other societies, the third principle could result in a significantly larger number of people who take the initiative of evacuation.

The objectives of this study are as follows: (1) To review previous research on past disaster prevention training at elderly welfare facilities. (2) This paper examines the effectiveness of a workshop that the author conducted in the past, in which staff at elderly care facilities considered the impact of and countermeasures against disasters at their own facilities. Previous studies have identified methods for planning and professional training. However, no research has been found in which staff at elderly care facilities consider the impact and countermeasures of a disaster at their facility, and reflect and share their opinions in the facility's disaster prevention and mitigation plans. The following became clear from the workshop: (1) It was suggested that group work using the World Café method can provide a forum for sharing diverse perspectives and opinions, raising awareness, and promoting mutual understanding and communication among staff. (2) The results of discussions among staff could serve as an opportunity to raise awareness and review the facility's disaster prevention plan. (3) Anticipated disaster response issues at elderly welfare facilities were extracted, and a checklist of disaster prevention measures and plans was created. By holding more workshops like this one in the future, it may be possible to create a standard disaster prevention and planning checklist for elderly care facilities. In the future, we would like to implement a disaster prevention training plan that we have tentatively prepared based on this data and verify its effectiveness.

The concept of “potential cases” of disasters, where the possibility of an occurrence is high but no disaster actually happens, is not widely known to the public, except for some experts. In this study, we analyzed open data on the water levels of rivers in Japan using an index we developed to represent the history of “potential cases” of river flooding in an area. The results indicate that locations where river flooding has occurred in recent years tend to have a higher average value of the index and a relatively smaller value of standard deviation of the indices up to the year before the flooding, compared to locations where river flooding did not occur in recent years. These findings suggest the importance of focusing on "potential cases" underlying the occurrence of floods.

This study examined the characteristics and utility of different control devices used for experiencing tsunami evacuation behavior through virtual reality (VR). The three devices compared were hand controllers, treadmill-based locomotion devices, and wearable locomotion devices. AVR simulation replicating the coastal area of Kamakura City, Kanagawa Prefecture, was developed to analyze evacuation behavior based on data from experimental participants.

The results revealed the following characteristics for each device. The degree of simulator sickness was mild across all devices. In terms of usability, the hand controllers received high evaluations, whereas the treadmill-based locomotion devices were found to be less user-friendly. The wearable locomotion devices did not demonstrate any distinct strengths or weaknesses regarding usability. From the perspective of presence, the wearable locomotion devices received superior evaluations, although the requirement for attention to the real space occasionally detracted from the sense of presence. Additionally, no significant differences were observed between the three devices regarding changes in participants' awareness.

At 19:15 on August 8, 2024, the Japan Meteorological Agency was issued "Nankai Trough Earthquake Extra Information (Megathrust Earthquake Attention)." For approximately one week, residents were urged to "reconfirm their daily preparedness for earthquakes." Although the timing coincided with the period just before the Obon holidays, this study clarified what disaster preparedness actions residents actually took in response to the information. Given the nature of the Extra Information system, it is highly likely that similar announcements will continue to be issued in the future. Therefore, it is necessary to identify residents' intended actions in response to future announcements in order to enhance the effective use of such information. Accordingly, the aim of this study is to evaluate the effects of the recent issuance of Extra Information and to clarify how residents would think and act when future announcements are made. The historical background leading up to the implementation of the Nankai Trough Earthquake Extra Information system is outlined, followed by a discussion based on the results of a survey conducted three months after the announcement.

The results revealed four key findings. First, the information was effective particularly among individuals who already had a high level of disaster preparedness awareness. Second, plans involving trips to the seaside were particularly likely to be changed or canceled. Third, individuals who took preparedness actions during this event also showed a high intention to engage in disaster preparedness actions upon future announcements. Fourth, residents' evaluations of the information were found to be unrelated to their intentions for disaster-related actions.

In the Noto Peninsula earthquake on New Year's Day 2024, a tsunami warning was issued two minutes after the earthquake, and television stations broadcast special disaster programmes.

This study analyses what kind of caster comments the news anchors on the special disaster programmes used to advise residents to evacuate from the tsunami.

The results of the analysis of five programmes showed that news anchors delivered ‘calls for evacuation to higher ground’, such as ‘Please run to higher ground’, more frequently than during the Great East Japan Earthquake. There were also frequent caster comments urging early evacuation, such as “Run away now”. On the other hand, the‘tone of command’technique that attracted attention in newspaper reports was used only by NHK.

Secondly, the number of appearances of caster comments quoting ‘Great East Japan Earthquake’ as a keyword to encourage evacuation varied across the stations. In addition, the caster comments ‘tsunami evacuation building’ and ‘tsunami evacuation tower’ were rarely used.

Furthermore, an analysis of the number of appearances of “tsunami forecast region” showed that “Noto Area, Ishikawa Prefecture” did not appear the most frequently at the stage when tsunami warnings were being issued. It was only after the tsunami warning was announced that“Noto Area, Ishikawa Prefecture” appeared the most.

In the future, it will be necessary to discuss the purpose and intention of using tsunami evacuation caster

comments one by one, respectively, in preparation for tsunami disasters such as a Nankai Trough earthquake.

We conducted a survey one year before and two months after the Noto Peninsula earthquake in January 2024, and received two responses from about 2,000 people. We believe this is a valuable example of collecting questionnaires from the same people before and after an earthquake. Of these, we examined the relationship between pre-earthquake evacuation intentions and immediate post-earthquake behavior for the 960 people who experienced a seismic intensity of 4 or greater. Although the pre-earthquake survey focused on evacuation intentions related to wind and flood damage, "level of concern about the disaster" and "calling neighbors to evacuate in case of disaster" were relatively high factors, and having a family member who has difficulty evacuating had a positive effect on evacuation intentions, while having a pet had a negative effect. Evacuation drills had a small effect, etc.

The most influential factor on behavior in the post-earthquake questionnaire was the intensity of the shaking. It was confirmed that the intention to evacuate was related to the behavior of going outdoors during an earthquake. This suggests that evacuation intentions formed in advance lead to appropriate behavior when a disaster occurs. Freeze-in syndrome, which occurs in the immediate aftermath of a disaster, occurs regardless of the level of evacuation intention. Still, more than half of respondents use TV, smartphones, or both to gather information. If information is well communicated, it can help people escape the freeze-in syndrome. On the other hand, those who were indifferent to disaster preparedness and answered 'did not evacuate' in their evacuation intentions often said that they did nothing during the earthquake. This highlighted the problem of how to reach indifferent people who have no contact with the outside world in the event of a disaster.

In this research, we investigate the differences in "bosai" (the content of information communicated about disaster prevention) among multiple organizations, and investigating the different ways of thinking of each organization regarding "bosai", which is the premise of the differences. In addition to analyzing the factors, we also analyze what kind of effects are caused by the differences and to organize the impact of the differences and similarities through interview surveys and to consider the direction of improvement. The content of "disaster prevention," which is used as a term of communication in various situations, is classified as mainly includes "①disaster prevention as an philosophy or concept" and "②disaster prevention as more specific measures and actions." we placed government agencies such as the national government, prefectures, and municipalities as the "creators", ordinary residents as the "recipients" and businesses and individuals who are responsible for communicating "bosai" to recipients based on the information provided by the creators as the "senders" of "bosai". By conducting hearings and interviews with the "creators" and "senders," we were able to understand the underlying thinking behind each institution's "bosai" and analyze the effects of differences in "bosai". As a result, we found that differences in three perspectives - each institution's mission and philosophy, policy initiatives, and public awareness and information dissemination - led to differences in "bosai", affecting both creators, senders, and receivers, and we organized direction for consideration in improving these effects.